U.S. patent application number 10/960277 was filed with the patent office on 2006-04-13 for surface cleaning apparatus.
Invention is credited to Brian McGee, Chad Reese.
Application Number | 20060076035 10/960277 |
Document ID | / |
Family ID | 36144060 |
Filed Date | 2006-04-13 |
United States Patent
Application |
20060076035 |
Kind Code |
A1 |
McGee; Brian ; et
al. |
April 13, 2006 |
Surface cleaning apparatus
Abstract
A surface cleaning apparatus comprises a body including a
plurality of compartments. An elongate rotating brush arrangement
is positioned within and extends across a first compartment. An
electric motor is positioned in a second compartment for driving
the brush. The motor for the brush can be operated at a plurality
of speeds. A feedback loop maintains the selected speed during
operation, and the motor will automatically shut off if the brush
is unable to rotate.
Inventors: |
McGee; Brian; (Auburn,
AL) ; Reese; Chad; (Auburn, AL) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Family ID: |
36144060 |
Appl. No.: |
10/960277 |
Filed: |
October 8, 2004 |
Current U.S.
Class: |
134/6 ; 15/41.1;
15/52.1 |
Current CPC
Class: |
A47L 11/4011 20130101;
A47L 11/4069 20130101; A47L 11/33 20130101; A47L 11/4041
20130101 |
Class at
Publication: |
134/006 ;
015/041.1; 015/052.1 |
International
Class: |
A47L 11/24 20060101
A47L011/24 |
Claims
1. A surface cleaning apparatus, comprising: a) a body having a
first compartment and a second compartment; b) an elongate brush
that can be rotated extending across the first compartment; c) an
electric motor in the second compartment, said motor being capable
of rotating the brush at a plurality of discrete speeds; d) a belt
connecting the motor and the brush; e) a sensor for sensing a
rotational speed of the brush; and f) a feedback circuit operably
connected to said rotational speed sensor for maintaining the
rotational speed of the brush at a speed corresponding to one of
the plurality of discrete speeds.
2. The surface cleaning apparatus of claim 1, further comprising: a
sensor for measuring the current drawn by said motor to drive said
brush as a function of time; and an interlock circuit operably
connected to said current sensor and said motor, wherein when the
current drawn over a time period is measured to be greater than one
of a plurality of threshold values, the interlock circuit prevents
operation of the motor.
3. The surface cleaning apparatus of claim 1, further comprising: a
battery operably connected to the electric motor; and a recharging
interlock to prevent operation of the motor based on the battery
during a recharging period.
4. The surface cleaning apparatus of claim 3, wherein the
recharging period is from 1 hour to 24 hours.
5. The apparatus of claim 1, wherein said first compartment is a
forward compartment.
6. The apparatus of claim 5, wherein said first compartment
comprises a front wall having a thickness and having a bottom
surface at a higher elevation than a bottom surface of said body,
wherein said bottom surface of said front wall has a lip of
increased thickness relative to said thickness of said front
wall.
7. The apparatus of claim 6, wherein said bottom surface of the
front wall is inclined at an angle relative to the plane of the
sweeper body.
8. The apparatus of claim 6, wherein said front wall of said first
compartment further comprises an opening for admitting larger
particles into said forward compartment.
9. The apparatus of claim 1, further comprising a wall separating
the first compartment from at least one other compartment, wherein
the wall is inclined rearwardly.
10. The apparatus of claim 9, wherein the wall between the first
compartment and the at least one other compartment has an angle of
inclination of from 15 to 20 degrees.
11. The apparatus of claim 1, wherein the second compartment
comprises a sealing wall that seals off the second compartment from
at least one other compartment in the body.
12. The apparatus of claim 1, wherein the motor is capable of
rotating the brush at 3 or more discrete speeds.
13. The apparatus of claim 12, wherein the motor is capable of
rotating the brush at a first discrete speed of from 3500 to 4000
rpm, a second discrete speed of from 2500 to 2800 rpm, and a third
discrete speed of from 1900 to 2400 rpm.
14. The apparatus of claim 1, wherein the feedback circuit
comprises a proportional-integral-derivative compensated motor
drive.
15. A method for sweeping a surface, comprising: providing a
sweeper comprising: a body; one or more compartments in said body;
a brush that can be rotated in one of the compartments; and a motor
in a different compartment than the brush for rotating the brush,
the method comprising: rotating said brush at one of a plurality of
discrete speeds; sensing the rotational speed of the brush; and
restoring the rotational speed of the brush to one of the plurality
of discrete speeds.
16. The method of claim 15, further comprising: sensing current
provided to the motor for rotating said brush; comparing the sensed
current with a plurality of stored composite current-time cutoff
values; and stopping said motor when the sensed current exceeds a
current cutoff value for a time greater than the corresponding
cutoff time value.
17. The method of claim 15, wherein the motor is capable of
rotating the brush at 3 or more discrete speeds.
18. The apparatus of claim 17, wherein the motor is capable of
rotating the brush at a first discrete speed of from 3500 to 4000
rpm, a second discrete speed of from 2500 to 2800 rpm, and a third
discrete speed of from 1900 to 2400 rpm.
19. A surface cleaning apparatus, comprising: a) a body having a
first compartment and a second compartment; b) an elongate brush
that can be rotated extending across the first compartment; c) an
electric motor in the second compartment, said motor being capable
of driving the brush at a plurality of discrete speeds; d) a belt
connecting the motor and the brush; e) a sensor for measuring
current drawn by said motor to drive said brush as a function of
time; and f) an interlock circuit operably connected to said
current sensor and said motor, wherein when the current drawn over
a time period is measured to be greater than one of a plurality of
composite threshold values, the interlock circuit prevents
operation of the motor.
20. The surface cleaning apparatus of claim 19, further comprising:
a sensor for sensing the rotational speed of the brush; and a
feedback circuit operably connected to said rotational speed sensor
for maintaining the rotational speed of the brush at a speed
corresponding to one of the plurality of discrete speeds.
21. The surface cleaning apparatus of claim 19, further comprising:
a battery operably connected to the electric motor; and a
recharging interlock to prevent operation of the motor based on the
battery during a recharging period.
22. The surface cleaning apparatus of claim 21, wherein the
recharging period is from 1 hour to 24 hours.
23. The apparatus of claim 19, wherein the first compartment is a
forward compartment.
24. The apparatus of claim 23, wherein said first compartment
comprises a front wall having a thickness and having a bottom
surface at a higher elevation than a bottom surface of said body,
wherein said bottom surface of said front wall has a lip of
increased thickness relative to said thickness of said front
wall.
25. The apparatus of claim 24, wherein said bottom surface of the
front wall is inclined at an angle relative to the plane of the
sweeper body.
26. The apparatus of claim 24, wherein said front wall of said
first compartment further comprises an opening for admitting larger
particles into said forward compartment.
27. The apparatus of claim 19, further comprising a wall separating
the first compartment from at least one other compartment, wherein
the wall is inclined rearwardly.
28. The apparatus of claim 27, wherein the wall between the first
compartment and the at least one other compartment has an angle of
inclination of from 15 to 20 degrees.
29. The apparatus of claim 19, wherein the second compartment
comprises a sealing wall that seals off the second compartment from
at least one other compartment in the body.
30. The apparatus of claim 19, wherein the composite threshold
values are at least 10 amps for 1 second, at least 15 amps for 500
milliseconds, and at least 20 amps for 100 milliseconds.
31. A method for sweeping a surface, comprising: providing a
sweeper comprising a body; one or more compartments in said body; a
brush that can be rotated in one of the compartments; and a motor
in a different compartment than the brush for rotating said brush,
the method comprising: sensing current provided to the motor for
rotating said brush; comparing the sensed current with a plurality
of stored composite current-time cutoff values; and stopping said
motor when the sensed current exceeds a current cutoff value for a
time greater than the corresponding cutoff time value.
32. The method of claim 31, further comprising: rotating said brush
at one of a plurality of discrete speeds; sensing the rotational
speed of the brush; and restoring the rotational speed of the brush
to said one of a plurality of discrete speeds.
33. The method of claim 31, wherein the composite current-time
cutoff values are 10 amps for 1 second, 15 amps for 500
milliseconds, and 20 amps for 100 milliseconds.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a surface cleaning apparatus, such
as for a floor or upholstery, incorporating an elongate rotating
brush arrangement and an electric motor for rotating the brush.
BACKGROUND OF THE INVENTION
[0002] Sweepers provide a convenient tool for household cleaning
applications. Unlike vacuum cleaners, sweepers do not generate
suction to collect dirt and particles from a surface. Instead, a
sweeper relies on a rotating brush bar for dirt collection. As a
result, sweepers require less power than vacuum cleaners, and may
be adequately powered using a battery.
[0003] Conventional brush drives do not monitor the rotational
speed of the brush. The motor operates at a single speed, leading
to a single rotational speed for the brush. This leads to less than
ideal cleaning, as a given brush speed may not be effective for
collecting particles of various sizes and/or densities.
Additionally, depending on the type of surface being swept, the
rotational speed of the brush can vary as the surface can impede
the progress of the brush when the brush contacts the surface.
[0004] Another problem encountered when using a surface cleaning
device with a rotating brush bar is that the rotating bar can
become jammed during operation. When the brush bar stops rotating,
the motor can become overloaded and damage the motor. One possible
solution to prevent damage to the motor is to provide an interlock
to turn off the motor when the brush bar is unable to rotate. The
interlock can be implemented in various ways, such as by turning
off the motor when the current delivered to the motor exceeds a
threshold value. However, this type of interlock can pose problems,
as setting the interlock threshold to a level that guarantees safe
operation of the motor may also lead to triggering of the interlock
under routine operating conditions.
[0005] What is needed is a surface cleaning apparatus that can
address the various cleaning situations presented due to variations
in the types of dirt and particles that need to be collected. The
surface cleaning apparatus should have a brush that can be reliably
rotated at a given rotational speed. This will allow the user of
the surface cleaning apparatus to be able to select the appropriate
brush speed for the surface or the type of dirt or particle that
needs to be swept. The surface cleaning apparatus should also have
an interlock that provides for safe operation of the motor while
minimizing unnecessary shutdowns. Additionally, the surface
cleaning apparatus should allow for improved operation time and
battery lifetime.
SUMMARY OF THE INVENTION
[0006] This invention provides a surface cleaning apparatus which
overcomes, or at least ameliorates, at least some of the problems
of known apparatus.
[0007] In an embodiment, the invention provides a surface cleaning
apparatus comprising a body having a first compartment and a second
compartment. An elongate rotating brush extends across the first
compartment, while an electric motor resides in the second
compartment. Preferably, a belt connects the motor and rotating
brush to allow the motor to drive the brush. The surface cleaning
apparatus also includes a sensor for sensing the rotational speed
of the rotating brush and a feedback circuit operably connected to
said sensor for maintaining the rotational speed of the rotating
brush at a desired level. Preferably, the rotational speed of the
brush is maintained at a speed corresponding to one of a plurality
of discrete speeds.
[0008] In another embodiment, the invention provides a surface
cleaning apparatus including a body having at least two
compartments. An elongate rotating brush extends across the front
of the cleaning apparatus within the body. The body also contains
an electric motor for driving the brush. Preferably, a belt
connects the motor and rotating brush. The surface cleaning
apparatus also includes a sensor for measuring the current drawn by
said motor to drive said brush as a function of time and an
interlock circuit operably connected to the sensor and the motor.
In this embodiment, when the measured current during a time period
is greater than one of a plurality of threshold values, the
interlock circuit prevents operation of the motor.
[0009] In addition to the above embodiment the invention provides a
method for sweeping a surface. The method can be used with a
sweeper having a body, one or more compartments in said body, and a
rotating brush. In the method, the brush is rotated at one of a
plurality of discrete speeds. The rotational speed of the brush is
sensed, and if the rotational speed of the brush is different than
the selected speed of the plurality of discrete speeds, the
rotational speed is modified.
[0010] In still another embodiment, the invention provides a method
for sweeping a surface with a sweeper having a body, one or more
compartments in said body, a rotating brush, a motor for rotating
said brush, and a battery for driving said motor. The current
provided by the battery to the motor for rotating the brush is
sensed and compared with a plurality of stored composite
current-time cutoff values. If the sensed current exceeds a current
cutoff value for greater than the corresponding cutoff time value,
the motor is stopped.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a better understanding of the present invention and to
show more clearly how it may be carried into effect reference will
now be made, by way of example, to the accompanying drawings in
which:
[0012] FIG. 1 is a view of a surface cleaning apparatus according
to an embodiment of the invention;
[0013] FIG. 2 is a bottom view of a surface cleaning apparatus
according to an embodiment of the invention;
[0014] FIG. 3 is a side view of a surface cleaning apparatus
according to an embodiment of the invention.
[0015] FIG. 4 is a simplified block diagram of the operational
elements of a surface cleaning apparatus according to an embodiment
of the invention.
[0016] FIG. 5 is a block diagram providing additional detail
regarding the operational elements shown in FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Brush rotational speed can directly impact the cleaning
efficiency of a surface cleaning apparatus. Heavier or denser
objects can often be collected more effectively by a cleaning
apparatus having a higher rotational speed for the brush. By
contrast, lower density objects or particles that have a relatively
large surface area may be easier to collect using a cleaning
apparatus with a lower rotational speed. The lower rotational speed
will generate less air movement, thus reducing the chances that the
low density object or particle will be moved away from the brush by
air currents rather than being captured by the cleaning
apparatus.
[0018] This invention provides a sweeper with a brush having an
adjustable rotational speed. In various embodiments, the sweeper
can be set to one of a plurality of brush rotational speeds. For
example, in an embodiment the sweeper can have at least 2 discrete
brush rotational speeds, and preferably at least 3 discrete brush
rotational speeds. In addition to having a plurality of speeds
available for sweeping, the sweeper can achieve and maintain a
selected brush rotational speed. Thus, the speed can be reliably
set to the value that provides the best sweeping performance.
[0019] In an embodiment, the rotational speed of the brush can be
selected to be at least one discrete brush rotational speed of from
3000 rpm to 4200 rpm. In another embodiment, the sweeper can
operate at a brush rotational speed of at least 3000 rpm, or at
least 3100 rpm, or at least 3200 rpm, or at least 3300 rpm, or at
least 3400 rpm, or at least 3500 rpm, or at least 3600 rpm, or at
least 3700 rpm, or at least 3800 rpm, or at least 3900 rpm, or at
least 4000 rpm, or at least 4100 rpm. In another embodiment, the
sweeper can operate at a brush rotational speed of 4200 rpm or
less, or 4100 rpm or less, or 4000 rpm or less, or 3900 rpm or
less, or 3800 rpm or less, or 3700 rpm or less, or 3600 rpm or
less, or 3500 rpm or less, or 3400 rpm or less, or 3300 rpm or
less, or 3200 rpm or less, or 3100 rpm or less. In still another
embodiment, the sweeper can operate at a brush rotational speed of
from 3500 rpm to 4000 rpm.
[0020] In an embodiment, the rotational speed of the brush can be
selected to be at least one discrete brush rotational speed of from
2300 rpm to 3500 rpm. In another embodiment, the sweeper can
operate at a brush rotational speed of at least 2300 rpm, or at
least 2400 rpm, or at least 2500 rpm, or at least 2600 rpm, or at
least 2700 rpm, or at least 2800 rpm, or at least 2900 rpm, or at
least 3000 rpm, or at least 3100 rpm, or at least 3200 rpm, or at
least 3300 rpm, or at least 3400 rpm. In another embodiment, the
sweeper can operate at a brush rotational speed of 3500 rpm or
less, or 3400 rpm or less, or 3300 rpm or less, or 3200 rpm or
less, or 3100 rpm or less, or 3000 rpm or less, or 2900 rpm or
less, or 2800 rpm or less, or 2700 rpm or less, or 2600 rpm or
less, or 2500 rpm or less, or 2400 rpm or less. In still another
embodiment, the sweeper can operate at a brush rotational speed of
from 2500 rpm to 2800 rpm.
[0021] In an embodiment, the rotational speed of the brush can be
selected to be at least one discrete brush rotational speed of from
1600 rpm to 2800 rpm. In another embodiment, the sweeper can
operate at a brush rotational speed of at least 1600 rpm, or at
least 1700 rpm, or at least 1800 rpm, or at least 1900 rpm, or at
least 2000 rpm, or at least 2100 rpm, or at least 2200 rpm, or at
least 2300 rpm, or at least 2400 rpm, or at least 2500 rpm, or at
least 2600 rpm, or at least 2700 rpm. In another embodiment, the
sweeper can operate at a brush rotational speed of 2800 rpm or
less, or 2700 rpm or less, or 2600 rpm or less, or 2500 rpm or
less, or 2400 rpm or less, or 2300 rpm or less, or 2200 rpm or
less, or 2100 rpm or less, or 2000 rpm or less, or 1900 rpm or
less, or 1800 rpm or less, or 1700 rpm or less. In still another
embodiment, the sweeper can operate at a brush rotational speed of
from 1900 rpm to 2400 rpm.
[0022] This invention also provides a surface cleaning apparatus
with an automatic shutoff feature that can stop operation of the
surface cleaning device based on multiple, independent shutoff
threshold values. In an embodiment, the threshold values are a
composite of a current value and time the current has exceeded the
threshold. These composite thresholds allow for an automatic
shutoff feature with greater flexibility. In the case of a larger
current spike, it may be desirable to stop operation of the motor
in as little time as possible. On the other hand, a smaller current
spike may have a low probability of damaging the motor, and thus
the motor can be allowed to operate for a longer period of time
before shutdown is necessary.
[0023] By having multiple stored current/time composite thresholds,
the motor can be protected against damage while avoiding
unnecessary shutdowns of the surface cleaning device due to less
severe spikes in the current. Any number of thresholds can be
established, including two thresholds, or three thresholds, or four
thresholds, or five or more thresholds. In an embodiment, the
current/time composite thresholds are established to shut down the
motor when the current is 10 amps or greater for a specified period
of time, or 12.5 amps or greater for a specified period of time, or
15 amps or greater for a specified period of time, or 17.5 amps or
greater for a specified period of time, or 20 amps or greater for a
specified period of time. In an embodiment, the current/time
composite thresholds are established to shut down the motor when
the current exceeds a specified value for at least 1 second, or at
least 750 milliseconds, or at least 500 milliseconds, or at least
250 milliseconds, or at least 100 milliseconds.
[0024] Note that these thresholds are not mutually exclusive. If
the current is greater than 15 amps for a period of time, that time
period will count toward meeting both a 10 amp and a 15 amp
threshold requirement for shutting down the motor.
[0025] In still another embodiment, the invention provides a
surface cleaning apparatus that preserves the operational lifetime
of the battery. When recharging of the battery begins, a recharging
interlock prevents operation of the surface cleaning device based
on the battery state until a sufficient amount of recharging has
occurred. This ensures that the battery will be fully or nearly
completely charged before the next use. By avoiding incomplete
charging of the battery, the lifetime of the battery can be
improved.
[0026] In an embodiment, a selector is used to select an operating
mode for the sweeper, such as charging mode or sweeping mode. In
sweeping mode the battery can provide power to the motor. When the
selector is set for charging mode, the battery is recharged by a
charge adapter and is not available for powering the motor. In an
embodiment, when the surface cleaning apparatus is turned off, the
charging mode can be selected by connecting the battery to a charge
adapter. In another embodiment, once the selector is set for
charging mode, the selector will remain in charging mode until the
battery has been recharged for a predetermined period of time. This
minimum recharging period can be set to any convenient time, such
as at least 30 minutes, or at least 1 hour, or a time period from
ranging from 1 hour to 24 hours, or a time necessary to recharge
the battery from 0% charge to at least 90% (or at least 95% or at
least 100%) of a full charge, or another time period based on the
charging rate of the battery. In such an embodiment, once charging
of the battery has started, the surface cleaning device cannot be
operated using the battery as the power source until the battery
has been recharged for the predetermined minimum time.
[0027] In yet another embodiment, this invention provides a surface
cleaning apparatus that cleans more efficiently due to proper
selection of the length of the bristles on the rotating brush.
[0028] FIG. 1 depicts an embodiment of a surface cleaning
apparatus. The embodiment of FIG. 1 includes a body 100, preferably
moulded of one or more plastic materials. Body 100 can be composed
of one compartment, or body 100 can include 2 or more separate
compartments, such as a first and second compartment; a first,
second and third compartment; a forward and rear compartment; a
forward, intermediate, and rear compartment; or another combination
of compartments.
[0029] FIG. 2 shows a bottom view of the embodiment shown in FIG.
1. In this embodiment, body 100 contains an electric motor 205 and
a rechargeable battery pack 207. The battery pack can be composed
of a single battery or multiple batteries. Indicator 127, shown as
a light emitting diode in FIG. 1, indicates whether battery pack
207 is in need of charging. To charge the battery pack, the battery
pack may either be connected to a main supply whenever the
apparatus is not in use or at suitable times when the battery pack
has become depleted. In an embodiment, electric motor 205 and a
rechargeable battery pack 207 can be housed in a compartment within
body 100. For example, FIG. 3 shows an embodiment of a surface
cleaning device having a sealed rear compartment 303. In this
embodiment, electric motor 205 and rechargeable battery pack 207
are housed in sealed rear compartment 303. Placing the motor and/or
the battery in a separate sealed compartment reduces the risk of
dust or other contamination from reaching the motor and/or the
battery. This should reduce the risk that the motor and/or the
battery will be damaged or otherwise have reduced performance due
to contamination from the dust being collected by the sweeper. In
other embodiments, the motor an rechargeable battery pack can be
located at various locations within body 100, such as in the main
compartment of the body 100, or in one of two compartments, or in
one of three compartments, or in one of many compartments. As an
alternative to a rechargeable battery pack, the apparatus can
include disposable batteries or a disposable battery pack. In still
another embodiment, the surface cleaning apparatus can be powered
by connection to a main power source, such as by electrically
connecting the apparatus to a standard household alternating
current outlet.
[0030] In the embodiment shown in FIG. 1, a switch 108 is provided
to permit a user to turn the motor on and off as desired. Another
switch 104 is provided to permit a user to switch between various
discrete rotational speeds for the motor as desired. In an
embodiment, switch 104 is configured to raster up and down through
the possible speeds. Thus, if the motor speed was initially in the
"low" setting, consecutive pushes of switch 104 would result in the
following motor speed settings: Low-Medium-High-Medium-Low. In
another embodiment, consecutive pushes of switch 104 can result in
the following motor speed settings: Low-Medium-High-Low. In still
another embodiment, switch 104 is configured to change speeds
according to other patterns. Indicators 126 indicate the current
speed of the motor. For example, having one of indicators 126
active can indicate a low speed setting, two indicators can
indicate medium speed, while all three being on indicates high
speed.
[0031] Body 100 also houses a rotating brush assembly 111. In an
embodiment, rotating brush assembly 111 includes an elongate
rotating brush. Preferably, rotating brush assembly 111 is located
near the front of body 100 and extends across substantially the
entire width of the body. In an embodiment, the rotating brush
assembly is provided with two helically arranged rows of bristles.
Preferably, the rows are helices that twist in opposite directions
and meet substantially midway between the ends of the brush
assembly. At the location of rotating brush assembly 111, the
bottom body 100 is open to allow the bristles of the brush
arrangement to contact a floor, carpet or the like over which the
surface cleaning apparatus is to be moved. In embodiments where
body 100 includes multiple compartments, rotating brush assembly
111 is preferably located in a first compartment. In the embodiment
shown in FIG. 3, rotating brush assembly 111 is located in forward
compartment 309. For convenience a front wall 185 of body 100 can
be arcuate to allow the brush assembly to be placed as far forward
as possible while still having the forward wall surround the brush
assembly.
[0032] In the embodiment depicted in FIG. 3, the rotating brush
assembly 111 is located toward the front of body 100. In such an
embodiment, the surface cleaning apparatus preferably includes a
rearwardly inclined wall 315 located behind the rotating brush
assembly and between the brush assembly and a dust collection
volume. The rearwardly inclined wall allows debris, such as dust,
dirt and the like, to be propelled up the wall due to rotation of
the brush arrangement 111 and away from the opening where the brush
arrangement contacts the surface to be cleaned. This reduces the
likelihood of dust travelling back toward the brush assembly, even
if the body is inclined forward. The wall 315 extends upwardly to
about the same height as the top of the rotating brush assembly
111. In various embodiments, wall 315 is angled toward the rear of
the body at an angle of from 15 to 20 degrees, such as 16 degrees,
17 degrees, 18 degrees or 19 degrees.
[0033] In various embodiments, the length of the bristles is
selected to improve the cleaning performance of the sweeper.
Preferably, the bristle length is selected so that the bristles
contact a surface to be swept. Because the sweeper may be used on
tile surfaces, in an embodiment the bristles are long enough to
contact the grout between tiles. The grout between tiles can be at
a lower elevation than the tile surface. Thus, the bristle should
be long enough to reach this lower elevation surface. In an
embodiment, the bristle length is at least 1 inch, or at least 1.5
inches, or at least 2 inches, or at least 2.5 inches, or at least 3
inches.
[0034] When the sweeper is placed on a level surface, the bristle
bar will be at a certain distance from the surface. In various
embodiments, this distance may vary from 0.5 inches to 2.5 inches
or more. In order to have the bristles contact the surface to be
swept, the bristles should be longer than the distance from the
bristle bar to the surface. In an embodiment, the bristles are
longer than the distance from the bristle bar to the surface by at
least 0.05 inches, or at least 0.1 inches, or at least 0.15 inches.
In another embodiment, the bristles are longer than the distance
from the bristle bar to the surface by 0.2 inches or less, or 0.15
inches or less, or 0.1 inches or less.
[0035] In still another embodiment, the length of the bristles is
selected to maintain a desired distance between the end of the
bristles and a wall separating the brush assembly from the dust or
debris collection compartment. If the distance between the bristles
and the wall separating the brush assembly from the debris
collection compartment is too large, particles may fall down out of
the sweeper without being swept into the debris collection
compartment. In an embodiment, the bristle length is selected so
that the bristles contact the wall separating the brush assembly
from the debris collection compartment during rotation of the
brush. In another embodiment, during rotation of the brush, the
distance between the end of the bristles and the wall separating
the brush assembly from the debris collection compartment is 0.1
inches or less, or 0.2 inches or less, or 0.25 inches or less.
[0036] In embodiments where body 100 includes separate
compartments, a compartment can be included within the surface
cleaning apparatus for capturing dirt and particles. Preferably the
compartment for capturing dirt and particles is a compartment
located behind the rotating brush assembly. In such an embodiment,
the motor and/or the battery for the surface cleaning apparatus is
sealed off from the dust collection compartment. The motor and/or
battery can be sealed off in a rear compartment or in any other
convenient location in the body of the surface cleaning
apparatus.
[0037] The embodiment shown in FIG. 1 includes a removable dust
collection compartment 117. Removing the dust collection
compartment allows dust and debris to be emptied out of the surface
cleaning apparatus. Preferably, the dust collection compartment 117
has a lower wall or bottom, an upper wall or top, side walls to
prevent collected dust from travelling to other regions within the
body, and at least one wall formed by the outer wall of the body
100. Based on this construction, dust and other debris will
accumulate within the compartment 117. In the embodiment shown in
FIG. 1, the removable dust collection compartment 117 forms a
portion of the top, side, and bottom walls of body 100. In another
embodiment, the dust collection compartment is not removable, but
at least one wall of body 100 can be removed to allow dust and
debris to be emptied out of the dust collection compartment.
[0038] Optionally, body 100 can also include a headlight 128. In an
embodiment, headlight 128 is composed of three light emitting
diodes that are shielded by a plastic cover.
[0039] The brush assembly can be operably connected to the motor by
any suitable method. For example, the motor can be used to drive a
belt connected to the brush assembly. In an embodiment, the belt
can be housed in a separate compartment within the body to prevent
dust or debris from reaching the motor and/or the battery.
[0040] FIG. 1 also depicts the front of a cleaning apparatus
according to an embodiment of the invention. Bottom surface 189 of
the front wall 185 is at a higher elevation relative to the surface
being swept than the bottom surface of the sweeper body. In an
embodiment, the higher elevation of bottom surface 189 is achieved
by having the side wall of the body near the front wall rise away
from the surface to be swept. In an embodiment, in the vicinity of
the front wall, the side wall rises away from the surface to be
swept at an angle of at least 5 degrees and preferably at least 10
degrees. In other words, the front portion of the side wall and the
surface to be swept form an angle of at least 5 degrees and
preferably at least 10 degrees. In an embodiment, this angle is 20
degrees or less, preferably 15 degrees or less. In another
embodiment the bottom surface 189 of the front wall can also be
angled away from the surface to be cleaned. The angle of the bottom
surface relative to the surface to be cleaned can be any convenient
angle, such as the same angle as the rise angle of the front
portion of the side wall described above. In an embodiment, this
angle is at least 5 degrees and preferably at least 10 degrees. In
an embodiment, this angle is 20 degrees or less, preferably 15
degrees or less.
[0041] In embodiments of the surface cleaning apparatus where the
bottom surface of the front wall is elevated relative to the bottom
surface of the body, the body can be tipped forward to bring the
brush arrangement into closer contact with a surface being cleaned.
Tipping the body of the cleaning apparatus forward will bring the
brush assembly into a position where the bristles of the brush come
into contact (or come into closer contact) with the surface to be
cleaned. When the body is tipped forward, the bottom surface of the
faceplate may also come into contact with the surface to be
cleaned. The additional width of the bottom surface of the
faceplate provides a larger contact area for the bottom surface,
and thus reduces the tendency of the bottom surface to "dig in"
when cleaning a soft surface. Instead, the additional width aids
the surface cleaning apparatus in being able to slide along a
surface to be cleaned when in the tipped forward position.
[0042] In another embodiment, the front wall or faceplate of the
forward compartment includes a notch or opening. The notch or
opening increases the distance between the bottom surface of the
front wall and the surface being cleaned in the region of the
notch. The notch or opening provides a location on the front wall
of the surface cleaning apparatus where larger particles can be
admitted for collection. This is of particular value when the
surface cleaning apparatus is being tipped forward so that the
bottom surface of the front wall is in contact with the floor.
[0043] The height of the notch or opening can be any convenient
height that allows particles to be collected by the surface
cleaning apparatus while the body is being tipped forward. In an
embodiment, the height of the opening relative to the bottom
surface of the front wall is the same as the distance from the
bottom surface of the front wall to the bottom of the surface
cleaning apparatus body. For example, if the bottom surface of the
front wall is higher in elevation than the surface to be swept by 1
cm (when the body is not tipped forward), the elevation of the
bottom surface in the notch relative to the bottom surface of the
rest of the front wall would also be 1 cm. This would lead to a
total elevation for the bottom surface of the opening of 2 cm
relative to a surface to be swept. In another embodiment, the
height of the notch relative to the rest of the front wall is from
0.25 cm to 2.0 cm. In still another embodiment, the height of the
notch relative to the rest of the front wall is at least 0.25 cm,
or at least 0.5 cm, or at least 1.0 cm, or at least 1.5 cm. In yet
another embodiment, the height of the notch relative to the rest of
the front wall is 2.0 cm or less, or 1.5 cm or less, or 1.0 cm or
less, or 0.5 cm or less.
[0044] The width of the notch or opening can be of any convenient
size, as long as the width is small enough to prevent undue stress
on the front wall when the sweeper body is tipped forward to bring
the bristles into closer contact with a surface. Thus, the notch or
opening can have various widths, as the width of the front wall can
be from 3.5 inches to as large as 20 inches. In other embodiments,
the width of the front wall can be at least 5 inches, or at least
7.5 inches, or at least 10 inches, or at least 11.5 inches, or at
least 13 inches, or at least 14 inches, or at least 15 inches. In
an embodiment, the width of the opening is at least 10% of the
width of the front wall and preferably at least 15%. In an
embodiment, the width of the opening is 40% or less of the width of
the front wall and preferably 25% or less. FIG. 1 shows an example
of a notch or opening 195 in a front wall 185.
[0045] In still another embodiment, an auxiliary rotary brush may
be provided at that side of the rotating brush assembly. FIG. 2
depicts an example of an auxiliary rotary brush 212. Such an
auxiliary brush is able to sweep debris into the path of the brush
arrangement which might otherwise be missed. The auxiliary brush
may be driven by any suitable means, such as a friction/clutch
drive, gearing from the brush arrangement, or by friction with the
surface to be swept, and is suspended from and extends outwardly
beyond the body 100. The auxiliary brush may comprise a conical
and/or cylindrical body rotatable about an axis which is inclined
to the vertical by about 10 degrees so as to extend outwardly
beyond the body 100. Bristles protrude radially outwardly from the
periphery of the cylindrical body, but need not be perpendicular to
the axis of rotation.
[0046] In yet another embodiment, the aperture for collecting dust
and debris can be increased by moving or removing a portion or all
of the front wall of the surface cleaning apparatus. Moving or
removing a portion of the front wall exposes more of the rotating
brush assembly. This increases the ability of a user to expose a
surface to be cleaned to the rotating brush. The portion of the
front wall can be a sliding portion, a rotating portion, a
detachable portion, or any other type of portion that allows for
additional exposure of bristles to a surface to be cleaned.
[0047] During operation, a surface cleaning apparatus according to
the invention is placed on a surface to be swept. When the motor is
turned on, the motor drives the rotating brush assembly. This
allows the surface cleaning apparatus to sweep debris or dust up
into the body for collection, such as in a dust collection
compartment. Suction is not required for proper operation of the
device. However, in an alternative embodiment, the surface cleaning
apparatus of this invention can also be incorporated into a vacuum
cleaner.
[0048] When the surface cleaning apparatus is not in use, it can be
stored, for example, in a cupboard or the like, hung on a wall, or
plugged into a power source in order to recharge the battery.
[0049] In another embodiment, this invention provides an improved
way for controlling the operation of the power system and the brush
in a surface cleaning device. FIG. 4 depicts a simplified block
diagram of a control system for a surface cleaning device. To
operate the motor 405, current is supplied by battery 407. The
amount of current supplied by battery 407 is at least partially
controlled by speed compensation module 435, which receives
feedback from feedback network 455 regarding the actual speed of
the brush during operation via a control module 475, which can be a
single integrated circuit chip. The control module also controls
indicators 425, which provide a visible output so that a user can
determine the current operating mode of the surface cleaning
device.
[0050] During operation, the feedback network 455 monitors the
rotational speed of the brush. This information is passed to the
control module 475, which contains stored values for the desired
rotational speed of the brush based on the selected settings of the
surface cleaning device. The control module 475 passes this
information to the speed compensation module 435, which compares
the actual rotational speed of the brush with selected rotational
speed. If the actual speed differs from the desired, selected
speed, the speed compensation module 435 will change the power
delivered to the motor 405 (such as by changing the current) so
that the actual speed corresponds to the selected speed.
[0051] The combination of the feedback network 455, control module
475, and speed compensation module 435 also provides an interlock
to prevent overheating of the motor during a brush jam or other
event where the brush is unable to rotate or otherwise creates
higher loading than expected. During typical operation, the current
delivered to the motor will have a value in the range of 0-5 amps.
However, if the brush becomes jammed and thus fails to rotate, the
speed compensation module will attempt to increase the current
delivered to the motor in order to increase the brush speed. If
allowed to continue for an extended period of time, this could
result in damage to the motor. To prevent this, the current
delivered to the motor is also monitored as a function of time. The
current level over time is compared to a series of stored
current/time composite threshold values. If the current delivered
to the motor remains above a threshold current value for longer
than the corresponding time threshold value for that current, the
speed compensation unit will cut power to the motor.
[0052] The embodiment shown in FIG. 4 includes a battery for
providing power to the motor. In an alternative embodiment, the
motor can be powered by a main power source, such as by connecting
the motor to an alternating current source using a standard wall
outlet. Other methods for providing power to the motor will be
apparent to those of skill in the art.
[0053] FIG. 5 depicts another embodiment of a control scheme for a
surface cleaning apparatus. In FIG. 5, motor 505 still receives
power from battery 507, but a selector module 545 resides between
the motor and battery. The selector 545 controls whether battery
507 is in operating mode or in charging mode. When the selector is
set for operating mode, the battery can provide power to the motor
505. When the selector is set for charging mode, the battery is
recharged by charge adapter 547 and is not available for powering
the motor. In an embodiment, when the surface cleaning apparatus is
turned off, the charging mode can be selected by connecting the
battery 507 to charge adapter 547. In another embodiment, once the
selector is set for charging mode, the selector will remain in
charging mode until the battery has been recharged for a
predetermined period of time. In such an embodiment, once charging
of the battery has started, the surface cleaning device cannot be
operated using the battery as the power source until the battery
has been recharged for the predetermined minimum time.
[0054] In the embodiment shown in FIG. 5, battery 507 should supply
current to motor 505 at a relatively constant voltage during
operation of the motor. Voltage sensor 559 monitors the battery
voltage and passes the voltage information to control module 575.
If the voltage of battery 507 changes to a value outside of a
predetermined range, control module 575 activates battery indicator
528 to indicate a problem with the battery. Battery indicator 528
is preferably a light-emitting diode (LED), although other types of
light sources or other indicators may be used. When power is being
delivered to the motor during operation, control module 575 also
turns on headlights 528, which are also preferably LEDs.
[0055] During operation, a user of the surface cleaning device may
set the brush speed to a predetermined speed setting. In an
embodiment, the brush speed may be selected to be one of three
speeds. The speed is selected by the user using speed selector 556.
This value is passed on to control module 575, which sends a signal
to speed indicator 526 to provide an indication of the selected
speed. In an embodiment, speed indicator 526 comprises 3 LED's. The
speed can then be indicated by illuminating the LED's in
correspondence to the selected speed. The actual speed of the brush
(or alternatively the motor) is measured by speed sensor 558. The
current being provided to the motor is also measured by current
sensor 557. These values are also collected by control module
575.
[0056] During operation, control module 575 passes the selected
speed value, the measured speed value, and the measured current
value to motor drive 535. In an embodiment, motor drive 535 is a
proportional-integral-derivative (PID) compensated pulse-width
modulated motor drive. The motor drive compares the selected speed
value with the measured speed value. If the selected and measured
speeds are different, the motor drive changes the speed of motor
505, such as by changing the current delivered to the motor. The
motor drive will continue to change the speed of the motor until
the selected speed and measured speed values are equal, or equal to
within a predefined tolerance.
[0057] An exception to the above-described operation is when an
excessive current is delivered to the motor. As described above,
the measured current value is tracked as a function of time and
compared to composite current/time threshold values. If the
measured current value exceeds a current threshold for the
corresponding time, motor drive 535 cuts the power to motor
505.
[0058] Thus the illustrated surface cleaning apparatus of the
present invention incorporates an electrically driven brush
arrangement that can be reliably set to one of a plurality of
rotational speeds. The brush arrangement is not driven by
frictional forces between the surface cleaning apparatus and the
surface over which it is to be moved. Thus, efficiency of the
apparatus is not dependent on the nature of the frictional contact.
Further, the apparatus does not rely on suction means to draw the
debris into a storage chamber. Thus, efficiency of the apparatus is
not dependent on the effectiveness of suction means and the
substantial power drain of suction means on the rechargeable
battery is avoided. The provision of the motor at the rear of the
apparatus eliminates the need for increased height should the motor
be positioned over the compartment for collecting dust and the like
and also provides effective full width cleaning which would not be
possible if the motor was to be positioned within the compartment
for collecting debris. In such a position, debris is likely to
accumulate around the motor and cause blockages. The illustrated
apparatus overcomes this problem by passing the drive means for the
brush arrangement at least partly through the debris
compartment.
[0059] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *